Fenestration
Originating in the early 19th century, "Fenestra," a Latin word for "window," is used to describe a hole in an anatomical structure.[1][2] Its derivative, "fenestration," meaning the surgical creation of such an opening, has, however, been more widely used to describe a natural luminal separation in an artery.
Intracranial arterial fenestrations are reported to be more common at the anterior communicating arterial complex and basilar artery.[3]
Cases
1
This patient presented with diffuse Fisher grade 4 SAH in the basal cistern. The outside hospital's CTA reported left V4 dissection vs. aneurysm (though of poor quality). However, a repeat CTA at our institute suggested a fenestration (A). Vessel wall MRI also showed no significant contrast enhancement (B, C).
Diagnostic cerebral angiography confirmed a left V4 fenestration (D, E). No cause of the hemorrhage was found, suggesting perimesencephalic non-aneurysmal subarachnoid hemorrhage. (F): right PICA and left AICA are dominant.
2
This patient presented with a ruptured left MCA aneurysm. There is an incidentally seen small basilar artery fenestration near the origin of the right AICA. The VAs are co-dominant, thus presenting an interesting contrast dilution pattern in the BA.
3
This left ICA injection shows a small left M1 fenestration.